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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma 25-hydroxyvitamin D concentrations and bone histomorphometry were investigated in 24 grossly obese subjects. The mean plasma 25OHD concentration was significantly lower in the obese group than in age-matched, healthy controls. Subnormal values were found in four obese subjects and in a further two subjects, who were investigated at the end of the summer, plasma 25-hydroxyvitamin D levels were at the lower end of the normal winter range. Bone histology was abnormal in two patients. In one, mild osteomalacia and secondary hyperparathyroidism were present while in the other patient the appearance suggested increased bone turnover, possibly as a result of healing osteomalacia. We conclude that gross obesity is associated with an increased risk of vitamin D deficiency, probably because of reduced exposure to uv radiation. Histological evidence of metabolic bone disease may also occur. Preoperative vitamin D deficiency may contribute in some patients to the development of metabolic bone disease after intestinal bypass.
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PMID:Vitamin D status and bone histomorphometry in gross obesity. 730 77

In this review, which only partially covers the data available, it is pointed out that the evaluation of the results of jejunoileostomy may depend upon the criteria used by the observers, and disclosure of the true effects of the operation may depend upon the long-term follow-up of the patients. With increasing length of observation, it has become apparent that problems such as vitamin D deficiency, renal stone formation, continued steatorrhea, gallstones, zinc and copper deficiency, and even renal failure may be seen with disturbing frequency. Some of these may be preventable, others may be correctable and, indeed, the overall incidence of genuinely severe problems may, in the long run, be sufficiently low so as to make the benefits of jejunoileostomy outweigh the hazards. The rate of patient satisfaction is high, quality of life is generally improved and psychosocial and economic benefits of jejunoileostomy are apparent. The operation may also be a better alternative than the physical hazards of continuing obesity. Whether or not gastric bypass represents a true improvement over jejunoileostomy will depend upon the conclusions reached after applying to it the same searching scrutiny that is being used to examine the long-term results of jejunoileostomy.
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PMID:Assessment of jejunoileostomy for obesity--some observations since 1976. 735 16

The degree of bone mineralization, estimated as the bone phosphorus/hydroxyproline ratio (P/Hypro), was studied in 33 patients who had undergone jejunoileal bypass surgery for massive obesity. Low values of bone P/Hypro are expected in osteomalacia. We found an elevated mean bone P/Hypro (p < 0.001) with the highest values in patients with the longest postoperative periods (rS = 0.65, p < 0.001). The study indicates that bypass surgery, in spite of vitamin D deficiency, is associated with an increased average degree of bone mineralization or a defect in bone collagen synthesis.
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PMID:Elevated bone phosphorus/hydroxyproline ratio following jejunoileal bypass surgery. 744 10

The surgical treatment of obesity can have adverse effects on bone, but there are few published data on the effects of vertical-banded gastroplasty. Serial measurements of bone mineral density at the lumbar spine and three upper femoral sites, using dual-energy X-ray absorptiometry, and also of biochemical indices of bone and mineral metabolism at intervals up to 2 years after operation were performed in 18 patients with morbid obesity who had vertical-banded gastroplasty. Bone mineral density measurements were also made in age- and sex-matched non-obese controls. Bone density before operation was significantly greater in the obese than in the controls (P < 0.02 at all sites). The obese patients lost weight rapidly after vertical-banded gastroplasty (mean weight loss 29 kg at 1 year, P < 0.001). This was accompanied by a measurable loss of bone density from the trochanter and Ward's triangle sites in the upper femur (P < 0.05), but not from the lumbar spine. Bone density values remained stable over 14 months in the controls. Hydroxyproline excretion increased significantly (P < 0.005), indicating an increase in bone resorption. Alkaline phosphatase levels decreased significantly (P < 0.001), but this probably represents the reversal of hepatic steatosis. There was no evidence of hyperparathyroidism or vitamin D deficiency. In conclusion, vertical-banded gastroplasty causes modest bone density loss from femoral sites, but not the lumbar spine. The difficulties of assessing bone density changes in the obese are discussed.
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PMID:Effects of vertical-banded gastroplasty on bone and mineral metabolism in obese patients. 894 76

Although vitamin D deficiency has been well-documented following gastric bypass surgery, there are few studies of vitamin D status in the non-operative morbidly obese patient. We examined 25-hydroxyvitamin D (25-OHD) levels in 60 morbidly obese pre-operative females; 62% of them had 25-OHD levels below normal range (16-74 ng/ml) which were not associated with reductions in serum calcium or phosphorus, liver or kidney dysfunction, and were not significantly correlated to patients' age. However, 25-OHD levels were significantly (p < 0.0001) and negatively correlated to body mass (r = -0.49). These data suggest that low vitamin D may be associated with obesity per se. Hypovitaminosis D, when it is found in post-bariatric surgery patients, may not be caused by the surgery since it may have been present to some degree pre-operatively.
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PMID:Vitamin D Deficiency in the Morbidly Obese. 1075 56

The effect of calcium infusion was studied in patients with renal tubular acidosis (RTA) and secondary hyperparathyroidism. Both developed after jejunoileal bypass operation (JIB) for morbid obesity. In three of four cases the acidification defect was abolished, probably due to a decrease of serum parathyroid hormone. As we found RTA in 9% (95% confidence limits 2-21%) of our patients, screening for acidosis is recommended in obesity patients after malabsorptive operations. RTA can be verified through an ammonium loading test. Before deciding on re-establishing bowel continuity due to RTA, we suggest that patients be evaluated for secondary hyperparathyroidism and vitamin D deficiency by measurement of serum calcium, parathyroid hormone and vitamin 1.25(OH)&inf2D&inf3;, and any calcium and vitamin D deficiency be corrected. An intravenous calcium loading test can predict the outcome of oral calcium and vitamin D supplementation. If RTA can be abolished through correction of calcium homeostasis, reoperation may be avoided. Before deciding on re-establishing bowel continuity in JIB patients with RTA, we therefore suggest that patients be evaluated for secondary hyperparathyroidism and any calcium deficiency be corrected.
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PMID:Renal Tubular Acidosis after Jejunoileal Bypass for Morbid Obesity: role of secondary hyperparathyroidism. 1077 22

Patients with end-stage renal disease have markedly increased risk for death from cardiovascular disease. Renal failure is associated with multiple metabolic and endocrinologic abnormalities, and these alterations are involved in advanced atherosclerosis and high cardiovascular risk. Increased insulin resistance index by homeostasis model assessment (HOMA-IR), a simple index of insulin resistance, was an independent predictor of cardiovascular mortality in nondiabetic patients on maintenance hemodialysis. Renal failure impairs lipoprotein metabolism leading to the atherogenic lipoprotein profile characterized by increased triglyceride-rich remnant lipoproteins such as intermediate-density lipoprotein, an independent factor of increased aortic stiffness. Non-high-density lipoprotein cholesterol, the sum of cholesterol of intermediate-density lipoprotein and other apoB-containing lipoproteins, is an independent factor associated with increased arterial thickness and a predictor of cardiovascular death in hemodialysis patients. The risk for cardiovascular death in hemodialysis patients is associated closely with hypertension and malnutrition, but not with obesity. The constellation of insulin resistance, dyslipidemia, hypertension, and malnutrition in renal failure suggests the presence of another type of metabolic syndrome promoting cardiovascular disease. In addition, vitamin D deficiency and abnormalities in calcium, phosphate, and parathyroid hormone levels increase the death risk from cardiovascular disease in renal failure. It is expected that treatment of these metabolic and endocrinologic alterations would improve the survival of patients with renal failure.
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PMID:Roles of metabolic and endocrinological alterations in atherosclerosis and cardiovascular disease in renal failure: another form of metabolic syndrome. 1549 Apr 3

Vitamin D deficiency may occur throughout the life cycle, and is described as an unrecognized epidemic. The risk of deficiency may be increased by darker skin color, overweight and obesity, and low vitamin D intakes, while living in low latitudes and not using protective measures against the sun may decrease risk. However, a recent study reported that Hispanic adults living in the high-sun-exposure area of Miami have a high prevalence of poor vitamin D status in the winter, suggesting that living at low latitudes alone does not protect against vitamin D deficiency. The vitamin D status of Hispanics needs further investigation, given the large number of Hispanics living in southern regions of the United States and the emerging role of vitamin D in numerous health disorders.
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PMID:Living in low-latitude regions in the United States does not prevent poor vitamin D status. 1602 64

Vitamin D3 is synthesized in the skin during summer under the influence of ultraviolet light of the sun, or it is obtained from food, especially fatty fish. After hydroxylation in the liver into 25-hydroxyvitamin D (25(OH)D) and kidney into 1,25-dihydroxyvitamin D (1,25(OH)2D), the active metabolite can enter the cell, bind to the vitamin D-receptor and subsequently to a responsive gene such as that of calcium binding protein. After transcription and translation the protein is formed, e.g. osteocalcin or calcium binding protein. The calcium binding protein mediates calcium absorption from the gut. The production of 1,25(OH)2D is stimulated by parathyroid hormone (PTH) and decreased by calcium. Risk factors for vitamin D deficiency are premature birth, skin pigmentation, low sunshine exposure, obesity, malabsorption and advanced age. Risk groups are immigrants and the elderly. Vitamin D status is dependent upon sunshine exposure but within Europe, serum 25(OH)D levels are higher in Northern than in Southern European countries. Severe vitamin D deficiency causes rickets or osteomalacia, where the new bone, the osteoid, is not mineralized. Less severe vitamin D deficiency causes an increase of serum PTH leading to bone resorption, osteoporosis and fractures. A negative relationship exists between serum 25(OH)D and serum PTH. The threshold of serum 25(OH)D, where serum PTH starts to rise is about 75nmol/l according to most surveys. Vitamin D supplementation to vitamin D-deficient elderly suppresses serum PTH, increases bone mineral density and may decrease fracture incidence especially in nursing home residents. The effects of 1,25(OH)2D and the vitamin D receptor have been investigated in patients with genetic defects of vitamin D metabolism and in knock-out mouse models. These experiments have demonstrated that for active calcium absorption, longitudinal bone growth and the activity of osteoblasts and osteoclasts both 1,25(OH)2D and the vitamin D receptor are essential. On the other side, bone mineralization can occur by high ambient calcium concentration, so by high doses of oral calcium or calcium infusion. The active metabolite 1,25(OH)2D has its effects through the vitamin D receptor leading to gene expression, e.g. the calcium binding protein or osteocalcin or through a plasma membrane receptor and second messengers such as cyclic AMP. The latter responses are very rapid and include the effects on the pancreas, vascular smooth muscle and monocytes. Muscle cells contain vitamin D receptor and several studies have demonstrated that serum 25(OH)D is related to physical performance. The active metabolite 1,25(OH)2D has an antiproliferative effect and downregulates inflammatory markers. Extrarenal synthesis of 1,25(OH)2D occurs under the influence of cytokines and is important for the paracrine regulation of cell differentiation and function. This may explain that vitamin D deficiency can play a role in the pathogenesis of auto-immune diseases such as multiple sclerosis and diabetes type 1, and cancer. In conclusion, the active metabolite 1,25(OH)2D has pleiotropic effects through the vitamin D receptor and vitamin D responsive elements of many genes and on the other side rapid non-genomic effects through a membrane receptor and second messengers. Active calcium absorption from the gut depends on adequate formation of 1,25(OH)2D and an intact vitamin D receptor. Bone mineralization mainly depends on ambient calcium concentration. Vitamin D metabolites may play a role in the prevention of auto-immune disease and cancer.
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PMID:Vitamin D physiology. 1656 71

Vitamin D deficiency is common in Arab countries particularly among women. This is the result of a low dietary intake of the vitamin, limited exposure to sunlight (a paradox in view of the high sunshine figures), skin colour, obesity and high parity. Apart from its adverse effects on bone in women and their offspring, vitamin D deficiency has the potential to cause or exacerbate heart failure through a number of mechanisms including activation of the renin-angiotensin system and increased arterial pressure. Accordingly, we propose that ensuring adequate vitamin D levels in Arab women will have a much greater impact on health than just the prevention of bone disease. In particular, we suggest that prevention and correction of vitamin D deficiency will reduce the incidence of heart failure and, for Arab women with established heart failure and vitamin D deficiency, improve cardiac function.
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PMID:Hypothesis: Correction of low vitamin D status among Arab women will prevent heart failure and improve cardiac function in established heart failure. 1682 39


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